The Effect Of Hydrogen For Quick Coal Liquefaction At High Temperature

In this paper, a17mL tubular resonance agitation microautoclave reactor is adapted to investigate the effect of hydrogen on Quick Coal Liquefaction at High Temperature (QCLHT) when Yanzhou coal is selected as object of study. Also, the effect of catalyst on QCLHT is studied. The main conclusions are as follows:It is found in the experiment that:at490℃, in5min, both in tetralin and naphthalene, the conversion rates are almost all the same at hydrogen or nitrogen atmosphere. It demonstrates that hydrogen didn’t participate in QCLHT. This conclusion is the same as the conclusions acquired in our research group before. There are two possible reasons for this phenomenon according to relevant documents. One possible reason is that the reaction time is too short for hydrogen to participate in the reaction. Another one is:hydrogen isn’t activated, so it doesn’t take part in liquefaction. In this paper, experiments are done to check these views.It is shown in the result that the conversion rate of Yanzhou coal in naphthalene solvent rise with the extension of time at490℃, but the extent is not large. It illustrates that reaction time is not the reason for the failure of hydrogen’s participating in the reaction in large amount. To check the factor of dissolving of hydrogen, the dissolving law of hydrogen is investigated at270℃. It is found that dissolution equilibrium is reached in30min. Liquefaction experiment is carried out. The results show that after being pre-dissolved in tetralin or naphthalene, the total conversion rate and oil production rate are all increased. The reason is that pre-dissolving of hydrogen precipitate hydrogen participating in QCLHT. According to swelling experiment, the increase in conversion rate in QCLHT is not caused by swelling but by pre-dissolving of hydrogen.To check the effect of catalyst on hydrogen activation in short time in QCLHT, ammonium maolybdate, zinc chloride, high dispersed iron-based catalyst and impregnated Fe2S3are selected as catalyst for liquefaction. The effect of these catalysts on coal pyrolysis is investigated, and the result shows that they don’t precipitate coal pyrolysis. Then, the effect of catalyst on precipitating hydrogen participating in QCLHT is studied. The result shows that the addition of ammonium maolybdate or zinc chloride doesn’t increase the conversion rate of QCLHT in tetralin or naphthalene solvent. While, high dispersed iron-based catalyst and impregnated Fe2S3precipitate hydrogen participating in QCLHT and increase the conversion rate. It can be concluded that the conversion rate of coal liquefaction can only be increase by proper catalyst.